Conduit box



R. P. DUNMIRE Feb, 25, 1930.

v I CONDUIT BOX Filed Feb. 16. 1926 ATTORNEYS.

Patented ,Feb. 25, 1930 UNITED STATES RUSSELL I PAUL DUNMIRE, F ERIE, PENNSYLVANIA, ASSIGNOR TO ERIE MAL'LEABL'E PATENT. OFFICE IRON COMPANY, or ERIE, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA coNnUI'r' BOX Application filed February 1 ,1926. Serial N sases.

This invention is designed to improve con- 7 duit boxes, particularly the knock-out type of box. Bymeans of this invention such'a box isconveniently and efficiently adapted for receiving'a conduitand preferably a threadless conduit. Features and details of the invention will appear from the specifica tion and claim.

' fitting.

Fig. 3 a section on the line 3-3 in Fig. 2. V

The invention is illustrated in the accompanying drawings as follows Fig. 1 showsa top View of-the box.

Fig. 2 an elevation of a conduit box wall giving an end view of the conduitmreceiving v Fig. 4 a detached view of a contractible clamping sleeve. j l'marks a conduit box, and 2 a knock-out opening in thebox.

A conduit-receiving fittingB has a 1 055 tion 4 extending from a Shoulder 5. T

fprojection 4 extends through an opening 2 and is provided with laterally readily contractible.

shoulders 6 at its inner end."

A wedge-piece 7 of U-shaped form has its branches 8 straddling the projection and extending under the shoulders 6. The

branches are slightly curved and .wedgeishaped so that the wedge maybe driven into place under the shoulders and the resiliency of the wedge provides for some slight variation in the dimensions of the parts The .wedge action of the wedge piece. the shoulder 5 against the face of theWall of the box and rigidly secures the fitting in clamps the opening.

The upper edge 9 of the wedge piece is slightly below the edgevof the box so that when the cover is in place on the box the acvcidental removal of the wedge isavoided. An extension 10 projects from the shoulder- 5 and has outwardly convergingwalls forming a tapered inner surface 11. A contractiextending A s at 1ts outer end which shoulder engages the nut 16 is arranged on these screw threads and adapteolto draw the sleeve into wedging engagement with the extension'so as to contract the sleeve into clamping engagement with a conduit A; The sleeve has a projectingflange 17 which forms a guard over the end of the conduit. V I A Y The projection is provided with fiat portions directly back of the shoulders 6, as

clearly indicated by dotted lines'in Fig. 2, which are engaged by the branches 8 of the U-shaped wedge thus locking the projection with the wedge and that the end of the wedge engages the wall of the box thus adding to the clamping action in locking the projecouter face of the wall of the box, said projection having oppositely disposed laterally projecting lips at its inner end and an outof-round portion adjacent to said lips; a

U-shaped .wedgepiece straddling the projection and engaging the lips, said U-shaped piece engaging the out-of-round portion of Y the projection "and locking the projection against turning in the U-piece and the U-piece' extending into contact and engaging the wall projection preventing its rotation through the engagement of'the U-piece with the wall projection; a fittingjextensionprojecting outwardly from the shoulder; and means for securing a conduit in the extension. 1

In testimony 'whereof'I have hereunto set my hand. I I V -RUSSELL PAUL DUNMIRE.

blesleeve'12 is arranged within the extension 10 and has a tapered surface conforming to the tapered surface 11. This sleeve has a longitudinal slot 13 terminating in a circumferential slot 14 rendering the sleeve The sleeve is provided with screw threads'l5 atits outer end and a 

